The 2000 Volkswagen Lupo used start-stop to achieve a fuel economy of 75 mpg in Europe on a diesel engine. Manufacturers haven't brought the tech to non-hybrids in the U.S., due to flaws in the EPA's fuel economy testing. (Source: Cars Plus Plus)

EPA is finally considering looking at the real value of stop start

Fuel economy ratings are supposed to provide an estimate of
the vehicles' real-world performance, helping customers determine how
efficient the vehicle is. Unfortunately, the ratings are only
as good as the tests that determine them, and in the U.S.
Environmental Protection Agency's case, those tests aren't very
good.

One significant oversight is stop
start technology. Overseas stop-start technology is
featured on a host of models, including the Audi A3 TDI, BMW
1-Series, BMW 3-Series, Mazda
2, Mini Cooper, Toyota Yaris. The technology is somewhat
expensive -- it's about $500 extra to install -- however, it's more
than worth it, providing fuel economy gains of around 7 percent.

The
EPA's flawed test cycle, though, currently only includes one stop so
the tech only earns automakers a 0.1 or 0.2 mpg increase in the
official EPA mileage estimates, despite much larger real world
gains. Without the extra rating to justify the extra costs,
manufacturers simply haven't been importing the tech on U.S. models.

Currently, the only vehicles to feature the tech are hybrids such
as the Toyota
Prius, Honda Insight, Chevrolet Malibu Hybrid and BMW
ActiveHybrid X6, as their electric systems allow the tech to be
implemented at a much lower costs. The net result is that at
the end of the day, the U.S. is trailing the rest
of the world in fuel economy.

Still the allure of models
like the Volkswagen Lupo, which received an estimated 75 mpg, keep
customers demanding that the EPA reconsider stop-start. Robert
Davis, Mazda's top product-development executive in North America,
comments, "In Japan, we're seeing anywhere from 7 to 9 percent
fuel economy gains from it. That's a jump from 33 to 37 miles per
gallon in a metro environment."

Audi of America spokesman
Christian Bokich complains, "We did not realize any savings in
U.S. EPA estimates based on required testing cycles."

The
EPA may finally be coming around and may try to fix its flawed test
procedure. It's taking public comment on stop-start
technologies, currently, and will look to announce new procedures in
April. Those procedures could finally include a test with more
stops. Mazda is urging automakers to join together to lobby the
EPA to give stop-start its just rewards. While this is
obviously a matter of personal interest to the company, it's also
important industry wide, and to U.S. consumers.

"The whole principle [of censorship] is wrong. It's like demanding that grown men live on skim milk because the baby can't have steak." -- Robert Heinlein